Piston structure



R. DAUB PISTON STRUCTURE Orgg'nal Filed E! 29. 1252 WMM PISTON STRUCTURERudolph Daub, West Caldwell, N. J., assigner or twenty percent to FrankA. Bower, New York, N. Y.

Original application May 29, 1952, Serial No. 290,738, now Patent No;2,755,151,dated July 17, 1956. Divided and this application July 12,1956, Serial No. 597,405

The portion of the term of the patent subsequent to July 17, 1973, hasbeen disclaimed 4 Claims. (Cl. 309-14) Thisinvention relates to pistonstructures and particularly to pistons of internal combustion engines.

The object of the invention is to provide a piston structure simple andinexpensive in manufacture and having surfaces of the piston groovesreinforced by hard metal wear plates distributed atwise around thepiston in a plane normal to the piston axis and anchored in place in themetal of the piston.

Further objects of the invention particularly in the formation of theplates to provide specially shaped parts for secure anchorage in thelighter metal of the piston will appear in the following specificationtaken in connection with the accompanying drawing in which:

Fig. 1 is a perspective view of a piston structure having a wall of agroove provided with wear plates in accordance with this invention;

Fig. 2 is a partial radial section on enlarged scale of the pistonstructure of Fig. l illustrating the reinforcement and the method offormation thereof;

Fig. 3 is a partial elevational view of the piston shown in Figs. l and2;

Fig. 4 is a partial plan view of a portion of a ring illustrating amodified formation of reinforcing plates for casting in the pistonstructure of Figs. 1, 2f and 3;

Fig.v 5 is a partial plan view of a further modification of a ringillustrating the formation of reinforcing plates in accordance with thisinvention;

Fig. 6 is a partial sectiona1 view of -a ring taken on line 6-6 of Fig.4;

Fig. 7 is a partial elevational view of another piston structure of thisinvention partly in section;

United .States Patent O Fig. 8 is a perspective view of a ring with wearplates for the structure of Fig. 6, the partial showing of the wearplates being illustrative of the formation which extends around theentire ring;

Fig. 9 is a partial perspective view of a modified plate ring of thetype illustrated in Figs. 7 and 8;

Fig. 10 illustrates another embodiment of metal expanding in width in aninward direction and having sloped edges.

In the embodiment of the invention shown in Figs. l to 3 the piston 15has head 16 and head groove 17 provided at its upper face with wearplates 18 cast in place in the metal of the piston.

These plates 18 are separate in the final piston structure shown andtheir spacing in even sequence around the groove 17 is attained byforming them as a continuous sequence of plates in an integral striphaving a radial section outlined at 20 in dot and dash lining in Fig. 2.A straight strip has a continuous edge portion 21 with plates 18projecting from it on one side in evenly spaced sequence and with theirends beveled as indicated at 22. The strip 20 is then bent into circularform (similar to Fig. 4) corresponding to the diameter shown in Fig. 2and is supported in place in the mold so as to have the aluminum alloymetal of piston 15 cast around the plates 18', the edge strip 21connecting plates 18' being preferably around the outside of the pistonperiphery as indi- ICC cated in Fig. 2. Then, upon machining of thepiston grooves, the ring or rim 21 is cut away and the plates 18 are cuton the outer edge and under surfaces to correspond to the grooving asshown in full line sectioning in Fig. 2. s

Preferably the plates 18' will have recesses for better securing them inplace in the alloy. For instance, as illustrated in Fig. 5, conicalcut-outs 23 are made at the under surfaces of opposite edges of theplates and in the casting operation metal will flow into these recesses23 so as to form underlying lips 24 of alloy on each side (Fig. 3).

These plates 18 are thus independent of each other imbedded in the alloyof the piston and preferably provided with interlocking protrusions ofthe alloy such as lips 24 securing them against release. The piston ringof groove 17 bears against the plates 18 and the groove surfaces betweenthem, and these groove surfaces, due to expansion at highertemperatures, tend to bulge slightly between the plates and arecorrespondingly worked against the hard upper surface of the piston ringand skin-toughened in very desirable manner. Thus, the lips 24 under theplate edges will be strengthened and pressed into close contact with therecesses 23 and at the same time are strengthened and hardened.

Similarly, where, as indicated in Fig. 5, the plates 25 joined by rim 26of the initial strip have recesses in the form of holes or orifices 27,these are filled with the alloy during casting and the metal protrudinginto the holes provides a composite surfacing of the plates in thegroove with skin hardening and toughening of the alloy surfaces underthe hammering of the hard piston ring.

As illustrated in Fig. 8, the plates 30 in addition to holes 31 may haveplain flanges 32 or ruffled anges 33 (Fig. 9) diverging outward at anyangle forming the alloy intrusions in the nal piston into dovetails 34between the plates and underlying the flanges and presenting flatsurfaces to the hammering hardening action of the piston ring.

In Fig. 10 the hard metal inserts or pieces 35, 36 are illustrated withtheir edges 37, 38 cut at angles spreading to greater width within theseat in the metal on each side of the groove 39 so that they areretained against axial movement. Similarly these inserts are slightlytapered to less width at their outer ends from an intermediate point 40so as to be retained against radial outward movement.

The system of this invention provides avery simple, adaptable, andeffective reinforcement applicable to one or more of the piston groovesurfaces with no substantial increase in cost and adding greatly to thelife of the piston and with improvement in the sealing action in thecylinder.

This case is a division of my co-pending application, Serial No. 290,738led May 29, 1952, now Patent No. 2,755,151, issued July 17, 1956, whichis a continuation in part of my application, Serial No. 225,533, filedMay 10,

1951, now Patent No. 2,685,729.

I claim:

l. A piston structure comprising a generally cylindrical piston head, apiston ring groove in said head and a series of reinforcinggroove-facing units of plate metal pieces independently cast in themetal of said piston as facings of groove surfaces and seated inrecesses therein having unit supporting surfaces in planes normal to theaxis of the piston, each unit having generally radially extending sideedges with generally radially extending surfaces interlocking axiallywith the metal of the piston and acting to retain it against axialdislodgement or loosening in service, and radial locking means formed bya cut out portion recessed at the side edge of said metal piece and ycooperating with a projection of the piston metal formed as a singlepiece at said piston head and having the shape of' said, cut:y outv totightly lock said metal piece against radia1 dislqdgement.. v

2. A piston structure as s et-forth in claim 1 wherein said cut outportion extends through only a portion of the thickness; ofk saidrnetalf piece l 3. A-pistong structure` asset-forth in claim 1 whereinsaid cut out portion formsthe axially interlockingmeans by= havingasurfacev facing said piston ring groove and said projection ispositioned between said surface and said;v piston ring groove tof form.a surface; adjacent to said metal piece as a1 portion of the wally ofthe piston ring groove to receiver the hammer-ing` of the piston ring tomaintainsaidprojection in tight locking contactv withA said cut out toprevent relative. axial movement of said metal piece, and oi saidvpiston head'` 4. A piston structure as set forth in' claim 1 whereinsaid radial locking means formed by radia1 edges on said metal piecediverging inwardly so that the width of said metal piece is greater atthe inner end than at the outer end and said piston head. cast to form awedged shaped portion engaging said edges to lock said metal piece insaid piston head.

References Cited in the le of this patent UNITED STATES PATENTS2,685,729 Daub Aug. 10, 1954 2,689,773 Brcnneke Sept. 21, 1954 2,755,151Daub July 17, 1956 2,771,328 Wainwright et al. Nov. 20, 1956

